PUCAI

The PUCAI includes six weighted items: abdominal pain, rectal bleeding, stool consistency, number of stools per 24 hours, nocturnal stools, and activity level. Since its original validation¹, the PUCAI has been externally explored and validated in numerus pediatric UC studies and has been endorsed by the European Medicines Agency (EMA) to replace endoscopic assessment in visits that do not include endoscopic assessment.

Feasibility and discriminatory ability of the PUCAI were demonstrated on 2,503 pediatric UC patients in the ImproveCareNow registry with all PUCAI items satisfactorily completed in 96% of visits. PUCAI remission cutoff scores (<10 points), as well as those for mild (10-34 points), moderate (35-64 points), and severe (≥65) disease have been validated in several cohorts and found to have sensitivity, specificity, and an area under the receiver operating characteristic curve  (AUROC) >95% . In its ability to differentiate changed from unchanged children, the PUCAI has excellent responsiveness over time with an AUROC of 0.96 (95% CI 0.92-0.99). The PUCAI had high correlation with a health-related quality of life score. 

Importantly, the PUCAI is tightly correlated with endoscopic appearance. PUCAI-defined remission was not inferior to sigmoidoscopy for predicting long-term sustained remission. In two independent cohorts of children admitted for acute severe UC, the PUCAI accurately identified those who would require treatment escalation to second-line medical therapy or colectomy, with superior predictive validity when compared to five fecal biomarkers, including calprotectin. However, the PUCAI had insufficient correlation with endoscopic appearance in children with primary sclerosing cholangitis, was not validated in children with disease confined to the rectum and has a ceiling effect, whereby once the highest score as been reached (i.e. 85 points), further discrimination of disease activity is not possible.

The ESPGHAN-ECCO pediatric UC management guidelines incorporated the PUCAI in the determintation of initial medical treatment and evaluating response, while combining this score with fecal calprotectin as a tool to identify the subset of patients who have endoscopic inflammation despite a low PUCAI score. Indeed, PUCAI-defined disease activity at disease onset was found to be a strong predictor of one-year clinical outcomes in several multicenter pediatric studies, including the prospective PROTECT cohort.

Cutoff values of PUCAI to determine severity of disease: 
PUCAI < 10 (remission)
PUCAI 10-34 (mild disease)
PUCAI 35-64 (moderate disease)
PUCAI ≥ 65 (severe disease). 
A change in score of at least a 20-points corresponds to clinical response or worsening.